/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with this
 * work for additional information regarding copyright ownership. The ASF
 * licenses this file to You under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package org.apache.commons.exec;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Used by <code>Execute</code> to handle input and output stream of
 * subprocesses.
 */
public interface ExecuteStreamHandler {

	/**
	 * Install a handler for the input stream of the subprocess.
	 * 
	 * @param os
	 *            output stream to write to the standard input stream of the
	 *            subprocess
	 */
	void setProcessInputStream(OutputStream os) throws IOException;

	/**
	 * Install a handler for the error stream of the subprocess.
	 * 
	 * @param is
	 *            input stream to read from the error stream from the subprocess
	 */
	void setProcessErrorStream(InputStream is) throws IOException;

	/**
	 * Install a handler for the output stream of the subprocess.
	 * 
	 * @param is
	 *            input stream to read from the error stream from the subprocess
	 */
	void setProcessOutputStream(InputStream is) throws IOException;

	/**
	 * Start handling of the streams.
	 */
	void start() throws IOException;

	/**
	 * Stop handling of the streams - will not be restarted. Will wait for pump
	 * threads to complete.
	 */
	void stop();
}
